A MODERN Atari Laptop! Finally possible exxos’s Atari, Amiga & retro forum

From your post, it seems you have a flat linearization for the K-Type sensors, correct? If not, please make sure to set the EGT sensor linearizations to “0” throughout. Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. There is a huge opportunity for 3D printing to offer teachers a new way to engage any and every student, no matter what their own challenges or their ages are. That’s why we’ve partnered with Kitronik to bring 3D printers to 5,000 classrooms in the UK. I believe that 3D printers should be usable by kids of all ages so that pupils have the opportunity to learn and realise their creative potential.

aursonline

I recall you previously indicated you wanted to measure to 0.1 ohm accuracy. New technologies can pose new problems for teachers, as they struggle to keep up. As such, it’s important that this new generation of 3D printers for schools are user-friendly and easy to use.

I need them to be 6 ohm or 8 ohm and with a grill , don’t forget 4 inch speakers. Last year I had to buy a new Scaler/counter, it had a BNC input, so I fitted BNCs to all my GM tube holders and converted my other scaler/counters to BNC. I had a similar problem one of my GM tube holders lost its PET plug, I tried to source a new one, but eventually gave up.

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In our own case, that’s why we built Robox so that people can start printing in just a few clicks. Despite the challenges facing the adults in the classroom, in fact most children are now computer-literate enough to frm coin price understand the fundamentals of computer aided design . Has anyone got a source for pre-made 8-pin molex connectors with a decent length pigtail? I’ve seen the ones posted for the 6-pin, but not the 8-pin molex kk.

The resolve appears to be cleverly written by the proven master of math around these parts, AllyCat and can be viewed in the code of post #1 here in this thread. I altered the values denoted by Symbol NUMERATOR and Symbol DIVISOR and Alan’s code did return the value I had hoped. I recall the effective resistance of the ADC input is said to be about 36K.

I believe 36 kohms is the value of the PICaxe “Weak Pullups”; AFAIK the PICaxe ADC uses a capacitive-divider method so the input impedance is basically “very high”. BUT, because the input has a sample-and-hold stage, Microchip recommend that the SOURCE impedance should not exceed 10 kohms. An absolute MAX current of 18mA is so important that I will be backing up the LM317 configuration with a second identical circuit in series. I know that sounds almost crazy and perhaps overkill, but in this case, it is more paramount than one may possibly imagine. If you set the lower end of the ADC range to, say, 3v, then the full 1024 bit ADC range now applies across 3v to 5v, not 0v to 5v.

Bits 31 & 30 are essentially STATUS bits and bit5 to bit0 are sub LSB’s that are ultimately insignificant noise. Not that I have finished looking around just yet, but the ADS1114 could be sufficiently suitable and offers which equates to steps, 187.5uV/step if using the 6.144v FSR or 125uV/step with a 4.096v FSR. For absolute surety, a couple ‘crowbars’ implemented in parallel will see the earth open up and swallow me whole before component failure poses any problem.

  • I could probably get it working with a bit more rework, but would rather just buy a premade wire at this point.
  • Here’s some code to try for the cheap version you could use it at 3v and a precision resistor not really required just enter the value.
  • From another forum post the 24-bit HX711 differential ADC was mentioned.
  • I am still of the view that charging up a capacitor and timing how long that takes may be a better way to increase resolution and accuracy.
  • I may be able to help there, but a prerequisite is proving your readings are what one would expect.
  • Technology is making our classrooms and education system an increasingly digital world, but 3D printing offers a way for teachers and students to connect this virtual world with the physical by creating tangible objects.

Ensure that the “5 volts” can NEVER significantly exceed that voltage, for example by adding a “crowbar” circuit, in its simplest form a shunt regulator such as a zener diode. Many years ago I was told that the construction of zener diodes is such that they “always fail safe” (in the context of protecting against over-voltage) to a short circuit. I don’t know if that’s still true – anything containing https://cryptolisting.org/ bond wires can “fuse” to an open circuit . Typically then repeated with a second, Reference, resistor so the stability of the capacitor is irrelevant, it’s just the ratio of two resistances / counts. Unless something is done to adjust how the ADC is converting, the readings from READADC10 won’t be sufficiently different to be able to determine the R1 better than to +/- 1 ohm resolution.

I seem to get about half of my bed to probe before one of the connectors wiggles loose, causing the effector to crash into the bed until the belt skips. Usually this happens a few times, and then the 6-blink pattern shows up once on the LED. At this stage I feel totally lost trying to programmatically extract the conversion result and then turn it into the desired figures to display on the LCD.

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If i take too long to reply, sorry my cat is sleeping on my laps. Turned out it was the two screw terminals towards the back of the picture i posted in an earlier post . Correct – Direct Connect preference and it’s the Bronze version on the RS site. Hi shmups members , i am need of some 4 inch speakers for a Vewlix Clone that is from ArcadeWorx.

The underlined component being the 24-bit conversion result I need to work with. Here’s some code to try for the cheap version you could use it at 3v and a precision resistor not really required just enter the value… Here’s some code to try for the cheap version you could use it at 3v and a precision resistor not really required just enter the value. For the beneficial purpose of this supreme forum, once I have achieved the goal, I will post the circuit along with the PICAXE code allowing it to be repeatable by any interested parties. The ADC is undoubtedly a high impedance input, as such for example a 1K resistor could be placed between the ADC input and sense point with a negligible effect to the signal.

I was thinking about something similar but wasn’t sure how it could be implemented. The first way you ensure that a circuit is accurate and reliable is to ensure that all components are operating well within their ratings. If a device is “only capable of supplying 10 mA” then it should be operated at 5 mA, or even 2 mA.

Not really his fault as this was a totally new type of job for him. I think the source of the issue might be that I’m using solid core Cat 6 cable, which is a bit stiff, and seems to exert some torque on the connector. You can have a modern full HD software compatible Atari laptop! I’ve been looking for a raspberry pi powered laptop for a long time and finally this is a reasonably priced unit. There are already tools online available to help teachers to take the first steps into designing on a 3D printer, such as TinkerCAD .

aursonline

Put that in parallel with a 510R reference resistor and it will change that. If put across the resistor to test it will affect the circuit non-linearly. Firstly, by putting any device (e.g. current limiter) in series with the voltage Reference, you appear to have largely eliminated it’s function of being an accurate Reference voltage ! Also, the mantra for achieving high reliability is generally to KISS .

Schools have traditionally struggled to justify the cost of fully equipped design and technology labs, which has made encouraging the level of creativity 3D printing can evoke a challenge for many teachers. These larger-style labs also require constant supervision by staff and teachers in order to prevent any accidents – another fear for many in the education system. However, 3D printing has the potential to change this perception and experience for students the world over. Technology is making our classrooms and education system an increasingly digital world, but 3D printing offers a way for teachers and students to connect this virtual world with the physical by creating tangible objects. Just make sure you have a spare 6 DIN spaces in your switchboard and a sparky that can understand a basic circuit diagram so that the meters can be wired in correctly. I basically did everything but turn the screwdriver when the sparky was installing my meters.

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This is true, however in this case is resolved by taking feedback from the output side of the current limiter in turn creating an offset to compensate any error. I don’t know exactly what you are doing but it sounds on par with measuring the resistance of a detonator coil inside a brick of C-4, something medical related, something with massive adverse consequences when it goes wrong. The responses are greatly appreciated and I am eternally grateful for the loan of your brain’s. I am still of the view that charging up a capacitor and timing how long that takes may be a better way to increase resolution and accuracy.

aursonline

If it’s essential to use a fixed 5 volts rail, you can still lower the effective driving resistance by putting another resistor in parallel with R1. For me, Thevenin’s theorem is probably the second most useful formula after Ohm’s Law. It depends if you want a resolution of 0.1 ohm at the 310 ohms value. If you do, then that 0.03 % “accuracy” opens a real can of worms. What I can’t figure out is how to effectively get my values into a SYMBOL/S on the fly in order to process my required calculations a number of times.

Jeremy Leach’s 32-bit Maths

So, as hippy indicated, the ADC also needs a “protected” supply voltage and a suitably high resistance in series with its input . To improve the “percentage” resolution, you need a lower series resistor, but this would of course increase the current and power dissipation in the resistors. To resolve to 0.1 ohm with a 10 bit ADC needs a series resistance of 100 ohms.

Blog: Huge potential for 3D printing in schools around the world

I could probably get it working with a bit more rework, but would rather just buy a premade wire at this point. The conversion result I need to work with is from bit6 to bit29 from what I read in the datasheet. This chip is rather impressive, does quite a stable job with my attached circuit and is very simple to get data returned. My very simple program reliably returns a repeated conversion result. From another forum post the 24-bit HX711 differential ADC was mentioned. That might be of interest because it seems designed for load-cells in everyday products which are usually styled in some sort of Wein Wheatstone Bridge configuration.

MUST the resistor under test be on the positive side of the Reference resistor ? That makes the whole measurement much more difficult. Thevenin really isn’t very difficult and sometimes can be extremely useful (Google might find a more User-friendly description than Wikipedia). Basically you just replace any voltage sources (e.g. the power supply) with a short-circuit and remove the load (e.g. the DUT) to calculate the desired resistances and voltages. The most difficult part is calculating the value of resistances connected in parallel, but here an “estimate” or an on-line calculator may be sufficient. My “Edit” above obviously doesn’t meet your revised specification, but may give an idea of what factors need to be considered.

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